condensation/furniture on rads and outside walls - PigletJohn?

[DIYtired]

Hello

I'm new so sorry if these questions are silly but I can't find the answers elsewhere. Warning: I'm v paranoid about our house (first ever house, hopefully forever house, I'm never moving again if I can help it).

Last year we bought a 40s solid brick wall (double brick) semi, with double glazing probably about 10 yrs old. We never drape wet washing on rads, we do sometimes dry indoors (about to buy tumble drier and/or dehumidifier!) and we air the house regularly. We get a little bit of condensation on windows, especially in our bedroom, but I've never seen evidence of mould. At the moment with it raining all the time, humidity in our room is about 55-60. When it was dry last week, humidity was 45-50.

My questions (2 separate issues) are:

• DP built a built-in chest of drawers in our bedroom - the 'bracing' side of it is directly on the outside wall, then there's a small air gap (1 inch wide), then the actual side of the COD, then the drawers. Having started to read about condensation, is it likely that we'll get mould on that wall? But I've read that mould only starts to form at humidity of 70?

• downstairs, on the side wall that doesn't have another house on the other side (ie outside wall), we've got a rad. We have the wonderful radflek behind, which helps. But before we finally get the flooring sorted, we've got the opportunity to change the rad to the opposite wall, so if heat escapes it will go through the wall into the lounge on the other side. I'm keen, but DP thinks it may upset the 'balance' of the house, and that having the rad on the outside wall may actually help to keep that outside wall dry and warm?

Any help would be really appreciated!

Thank you

I wouldn't worry about the position of the radiator.

Ventilation, especially of humid areas like bathrooms and kitchens, preferably with an effective extractor, will help a lot. Using a drier instead of draping will help a lot. If you breathe less in bed, that will help too. If your windows have a trickle vent opening, use that.

Condensation mould is typically seen inside or behind furniture that is against an outside wall as it is colder and the damp accumulates due to lack of airflow. Drilling a small hole through the wall to ventilate the gap will make it drier but colder. Some people try sticking expanded foam insulation on the wall.

If you're working on the floors, clear the airbricks of the cobwebs and accumulated dust to help ventilate the subfloor. Any damp patches under the floor suggest a water leak.

We live in a house with solid stone walls and get mould on the outside walls where we have furniture against them. There's not much you can do except improve airflow by moving furniture away from the walls. A thin sheet of expanded polystyrene does work but it doesn't look pretty so the only place I've done it is inside a built in wardrobe.

sorry for delay (Christmas). thanks v much for replies.

Is there anyway of telling if mould is forming on the wall without taking fitted chest of drawers apart?

nocake - do you know what level humidity you have inside your house?

PigletJohn - when you say 'don't worry about position of radiator' do you mean that moving it isn't worth the money, or that moving it won't upset the heating balance of the house?

I'll try to convince DP about drilling a hole - he's aghast that his (admittedly lovely) built in COD might have to come out. If only we'd known!

Thank you.

I don't think moving the radiator will make any significant difference.

That part of the wall immediately behind it will be a bit warmer, but the temp will drop away within a foot. Heating costs will be a tiny bit less as you will not be sending so much heat outside to warm the sky.

Our weather station is showing a humidity of 52% with humidity of 92% outside... but I wouldn't trust it to be accurate

Would using something like this help with your built-in?

Not sure if it could fit under the bottom drawer/in the void?

thanks very much. does anyone know if there is anyway of telling if mould is forming on the wall without taking fitted chest of drawers apart?

nocake - how quickly does the mold appear? and how does the sheet of expanded polystyrene work??

RunsWithScissors - good thought, I'll have a go!

Not sure of it would be conclusive, but my thinking would be to take out the drawers (if fully removable) stick you head in and give a good sniff.

You'd smell the mustiness right away I would think.

Good luck!